What Is Force?
An object continues to do what it is doing unless some external unbalanced force acts on it. So, forces play an important role in physics because It is the force only which allows motion of an object. Balanced forces do not cause things to move. They do not produce any acceleration. Unbalanced forces can change the state of motion of an object.
What Is Force?
Force can be defined as push or pull on an object which provides motion to an object. Every object on the Earth experiences various forces. Force is a vector quantity. So, it has a magnitude and a direction. Forces can never be seen, but its effects can be observed in the form of motion of an object. Pushing of chair, pulling of door are all the results of applied force. Force that we apply on an object can change the speed, direction, shape and size of an object. Forces can be balanced or unbalanced.
Balanced Forces And Unbalanced Forces
When an object is in equilibrium, that means, it is not moving with a changing speed or velocity, then net force acts on it is known as balanced force. When the number of forces acting on an object are such that their resultant force is zero, then the forces are said to be balanced. If the forces are balanced, then there can be two cases. An object may be at rest or an object will be in motion at a non zero constant velocity in a certain direction. In the first case, the object will continue to remain at rest. In the second case, the object will continue to stay in motion at the same velocity and in the same direction.
Balanced Force
The image shown above is a real life example of balanced forces. This person is pushing against the wall and the wall is not moving. That means, the wall is actually pushing back on this person with an equal force but in the opposite direction.
When an object is not in equilibrium, that means it is moving with changing speed or velocity, then the net force acting on that object is known as unbalanced forces. When the number of forces acting on the object are such that their resultant force is not equal to zero, then the forces are said to be unbalanced.
Unbalanced Force
The image shown above is an example of unbalanced force. When we kick the football, the football starts moving in the direction of a larger force acting on it. Hence, when we kick a football and it moves from one place to another, we can say that unbalanced forces are acting upon it. That means, the net force is not equal to zero. Unbalanced force is responsible for this kind of motion.
Effects Of Balanced And Unbalanced Forces
Balanced forces will cause no change in the speed of an object. When two unbalanced forces act in opposite directions, their combined force will be equal to the difference between the two forces. If the net force applied on an object is not equal to zero, that means, the force on one side is greater than the other, then the forces are said to be unbalanced forces.
Characteristics Of Balanced And Unbalanced Forces
Here are some interesting characteristics about balanced forces:
If a number of balanced forces are acting on a stationary object, then that object doesn’t change its state of rest. So, we can conclude that if a number of balanced forces are acting on an object which is at rest, then these forces can not result in the motion of the object which is stationary.
If a number of balanced forces act on an object which is in uniform motion, then the object continues to be in its state of uniform motion. That means these balanced forces can not change the state of uniform motion of an object.
Balanced forces neither produce motion in a stationary object nor can they stop a moving object.
Balanced forces can change the shape of an object even though they can not set a stationary object to motion or they can not set the object which is moving to rest.
Here, are some characteristics of unbalanced forces:
Unbalanced forces can change the state of an object from rest or uniform motion.
They can move a stationary object whenever the object is at rest.
They can stop a moving object.
They can change the speed of an object as well as the direction of the moving object.
Solved Examples
1. What force would be needed to produce acceleration in an object of mass?
Ans: Given: acceleration
mass
Here, we will use the relation
Therefore,
So, the required force is
2. Calculate the force to impart to a bus a velocity of in 10 seconds starting from rest. The mass of the bus is
Ans: Given: Here, the bus is starting from a rest position. So, initial speed of the bus is
Final speed of the bus
Mass of the bus
Time taken
We will use the relation to get acceleration,
Now, we will use the formula
So,
So, the required force is
Interesting Facts
If we apply a balanced force on any object, then that object would not change its state of motion or rest.
Newton’s second law explains to us that unbalanced force causes acceleration.
Sir Issac Newton developed laws of motion.
Conclusion
So, we can conclude that balanced forces do not allow the moving object to change its direction or its speed. If balanced force acts on an object at rest, then we can say that the object can not move. If unbalanced force acts on an object at rest, then the object will start moving in the direction of greater force.
FAQs on Balanced And Unbalanced Forces
1. State the difference between distance and displacement.
Here are a few points which show the difference between distance and displacement.
The actual path length between initial and final position is called distance. The shortest path length between initial and final point is called displacement.
Distance is a scalar quantity. So, it has only magnitude. Displacement is a vector quantity. So, we can say that displacement has magnitude as well as direction.
For the moving object, distance can never be equal to zero. Displacement can be zero.
Distance travelled by an object per unit time is called speed. Displacement travelled per unit time is known as velocity.
2. Define positive acceleration, negative acceleration and uniform acceleration.
Acceleration is the rate of change of velocity of an object with respect to time is called acceleration or change in velocity per unit time is defined as acceleration. It is a vector quantity. If the velocity of an object increases with time, then the acceleration of the object is said to be positive acceleration. If the velocity of the object decreases with time, then the acceleration of the object is said to be negative acceleration. Negative acceleration is called de-acceleration or retardation. An object is said to be uniformly accelerating when its velocity increases or decreases by equal amounts in equal intervals of time.
3. State Newton’s second law of motion.
The force required to change the momentum of an object depends upon the time rate at which the momentum of the object is changed. So,here the time period in which the momentum of the object has changed plays an important role. The second law of motion states that the rate of change of momentum of the object is directly proportional to the applied unbalanced force and it is in the direction of that force. More the force will be, the more the rate of change of momentum will be. We can conclude that if the rate of change of momentum increases, then the applied force also increases.
